Patient monitors for monitoring various physiological characteristics of a subject have been heretofore suggested and/or utilized (see, in general, U.S. Pat. Nos. 5,036,852, 4,506,678 and 4,713,558), some including means of transmission to remote receivers (see U.S. Pat. No. 5,022,402) or multiple modes of data reporting (see U.S. Pat. No. 4,475,558). Various emergency response systems, often utilizing multiple data transfer links, have also heretofore been suggested and/or utilized for linking a subject to a central response network (see U.S. Pat. Nos. 5,086,391, 5,091,930, and 5,128,979).
Such monitors and systems, however, have not addressed the need for on-site monitors which may be conveniently and comfortably used (i.e., which minimize discomfort of the subject), which can be used by untrained personnel, and which will reliably transfer information to, and thus alert, a care giver in a wide variety of situations and environments including, for example, subject disability (or in cases where the subject is sleeping and/or is an infant), transmission signal loss or distortion (due to data channel failure, transmission noise, stray signals, range limitations, or the like) and/or high noise environments.
While dual frequency transmitters and the like have been heretofore suggested and/or utilized in various settings (see, for example, U.S. Pat. Nos. 3,870,959, 4,367,458, 2,892,930 and 4,494,238), such transmitters have not been heretofore adapted for use in medical monitoring and/or do not in and of themselves resolve many of the above-addressed needs. Thus, improvements directed to increasing the reliability, comfort and ease of use of monitors employed to remotely monitor selected physiological parameters could still be utilized.